Predictors of disease activity during pregnancy in women with inflammatory bowel disease-a Danish cohort study

Background and aims: Inflammatory bowel disease (IBD) activity during pregnancy is associated with adverse pregnancy outcomes. We aimed to identify key clinical characteristics that predict disease activity during pregnancy.

Methods: Between January 2008 through 2021, we identified all singleton pregnancies among women with IBD recorded in patient and birth registries at a tertiary IBD centre in Denmark. Maternal and infant data were retrieved from medical records. Demographics, Physicians Global Assessment (PGA) of disease activity 6 months prior to pregnancy and in all three trimesters of pregnancy and pregnancy outcomes were recorded.

Results: In 609 pregnancies, we observed 603 (99.0%) live births. Disease activity in one or more trimesters was seen in 283 women (46.5%). UC phenotype was associated with an increase in risk of disease activity (adjusted OR = 2.6 [1.8-3.9]; p < 0.001). Disease activity within 6 months prior to conceiving (169 women [27.7%]) was associated with an increased risk of continuous disease activity during pregnancy (adjusted OR of 5.3 [3.5-8.2]; p < 0.001). Disease activity during a previous pregnancy was associated with an increased risk of flares in subsequent pregnancies (adjusted OR of 3.2 [1.5-6.6]; p = 0.002). Sustained clinical remission throughout pregnancy was associated with an increased probability of normal birth term, birthweight and low risk of fetal growth restriction (FGR) and stillbirth.

Conclusion: Predictors for disease activity include disease activity in a previous pregnancy and/or prior to conception, as well as UC phenotype. Reassuringly, women with IBD in remission are not at increased risk of adverse pregnancy outcomes.